feat: Invalidation and lazy reloading of implementations

The interface is a bit clunky, the "author" and the callback "data"
  have to be specified when adding (an) implementation(s) in order
  for this to work. But it does, and this is just a PoC, the interface
  could be cleaned up.
This commit is contained in:
Glen Whitney 2022-03-25 13:09:50 -07:00
parent 00a7f79552
commit 1c1ba91e48
4 changed files with 70 additions and 18 deletions

View File

@ -4,6 +4,6 @@ export default function create(pmath) {
return pmath(
'subtract',
[args => args.length === 2, (x, y) => add(x, negate(y))],
create)
create, pmath)
return pmath.subtract
}

View File

@ -6,11 +6,11 @@ export default function picomathInstance (instName) {
* as a function, it takes a name and 0 or more implementations add adds
* them to its poortf property named name, returning that property value.
*/
function fn (name, imps, author) {
function fn (name, imps, author, data) {
if (name in fn) {
fn[name].addImps(imps, author)
fn[name].addImps(imps, author, data)
} else {
fn[name] = poortf(name, imps, author)
fn[name] = poortf(name, imps, author, data)
}
return fn[name]
}

View File

@ -7,6 +7,9 @@
const addImps = (dest, imps, author) => {
if (imps) {
if (!Array.isArray(imps[0])) imps = [imps]
} else {
imps = []
}
if (author) {
if (dest.authors.has(author)) {
const [count, index] = dest.authors.get(author)
@ -15,15 +18,16 @@ const addImps = (dest, imps, author) => {
dest.authors.set(author, [imps.length, dest.imps.length])
}
for (const imp of imps) dest.imps.push(imp)
}
}
/* Create a TF, optionally adding some initial imps and further optionally
* registering them to an author. There are two advantages to author
* registration: (1) if the same author adds implementations, the prior imps
* will be deleted, and (2) the author can be invalidated, and the TF will
* lazily call the author back the next time it is called to re-add the imps.
* lazily call the author back with the given data the next time it is
* called, so that it can re-add the imps.
*/
export default function poortf (name, imps, author) {
export default function poortf (name, imps, author, data) {
/* This is the (function) object we will return */
function fn () {
for (const imp of fn.imps) {
@ -37,9 +41,39 @@ export default function poortf (name, imps, author) {
Object.defineProperty(fn, 'name', {value: name})
fn.imps = []
fn.authors = new Map() // tracks who made each implementation
fn.authorData = new Map() // tracks author callback data
addImps(fn, imps, author)
fn.addImps = (newI, author) => addImps(fn, newI, author)
if (author) fn.authorData.set(author, data)
fn.addImps = (newI, author, data) => {
addImps(fn, newI, author)
if (author) fn.authorData.set(author, data)
}
fn.invalidate = author => {
addImps(fn, null, author) // deletes the author's imps
fn.unshiftImp([() => true, (...args) => fn.reloadAndRecall(args)])
}
fn.unshiftImp = newImp => {
fn.imps.unshift(newImp)
for (const record in fn.authors.values()) {
record[1] += 1
}
}
fn.shiftImp = () => {
const oldImp = fn.imps.shift()
for (const record in fn.authors.values()) {
record[1] -= 1
}
}
fn.reloadAndRecall = (argArray) => {
fn.shiftImp() // throw ourself away, ha ha
for (const author of fn.authorData.keys()) {
if (fn.authors.get(author)[0] === 0) {
// imps count of 0 means the author was invalidated
author(fn.authorData.get(author))
}
}
return fn.apply(null, argArray)
}
return fn
}

View File

@ -21,13 +21,22 @@ describe('poortf', () => {
assert.throws(() => add('kilroy'), TypeError)
})
const defNumber = what => {
slate.addImps([args => typeof args[0] === 'number',
n => 'I am not number ' + (what+n)],
defNumber, what+1)
}
it('extends an empty tf', () => {
defNumber(2)
assert.strictEqual(slate(0, 'was here'), 'I am not number 2')
assert.throws(() => slate('Kilroy', 'was here'), TypeError)
slate.addImps([
[args => typeof args[0] === 'string', s => s + ' wuz here'],
[args => typeof args[0] === 'number', () => 'I am not a number']
[args => typeof args[0] === 'boolean', () => 'Maybe I am a number']
])
assert.strictEqual(slate('Kilroy', 'was here'), 'Kilroy wuz here')
assert.strictEqual(slate(2, 'was here'), 'I am not a number')
assert.strictEqual(slate(true), 'Maybe I am a number')
assert.throws(() => slate(['Ha!']), TypeError)
})
@ -36,6 +45,15 @@ describe('poortf', () => {
assert.strictEqual(add('Kilroy', 23), 'Kilroy23')
assert.throws(() => add(['Ha!'], 'gotcha'), TypeError)
})
it('can invalidate and lazily reload implementations', () => {
slate.invalidate(defNumber)
assert.strictEqual(slate.imps.length, 3) // reloader plus two non-number
assert.strictEqual(slate(1), 'I am not number 4') // 'what' is now 3!!
assert.strictEqual(slate('Yorlik', 7), 'Yorlik wuz here')
assert.strictEqual(slate(false), 'Maybe I am a number')
assert.strictEqual(slate.imps.length, 3) // reloader gone
})
})